TW201932989A - Semiconductor structure, semiconductor device, and method for using acoustic waves to detect overlay error - Google Patents

Abstract

An overlay mark structure includes a first periodic structure positioned on a chip, the first periodic structure comprising a material of a first layer disposed on the chip. The overlay mark structure further includes a second periodic structure positioned within the region of the chip adjacent the first periodic structure, the second periodic structure comprising a second material of a second layer disposed on the chip. The overlay mark structure further includes an acoustic wave transmitter device disposed on the chip and an acoustic wave receiver device disposed on the chip.

Description

Stack-to-symbol structure, semiconductor device, and method for detecting overlay error using sound waves

The present disclosure relates to a stacked pair mark structure, particularly a stacked pair mark structure that can detect overlap errors by using sound waves.

In the semiconductor integrated circuit (IC) industry, technological advances in integrated circuit materials and integrated circuit design have produced multiple integrated circuit generations, each integrated circuit generation has smaller and more generations than the previous integrated circuit generation. Complex circuit. As the integrated circuit evolves, the geometry (eg, the smallest component (or line)) that the process can make decreases, and the functional density (eg, the number of connected components per wafer area) typically increases. This miniaturization process offers advantages by increasing production efficiency and reducing associated costs. This miniaturization also increases the complexity of the integrated circuit process and manufacturing.

One of the challenges of semiconductor manufacturing is alignment. Semiconductor processes involve forming a plurality of patterned layers on top of each other. Each of these layers must be precisely aligned or the final device may not function properly.

Alignment techniques typically involve the use of overlay marks. For example, the various layers to be patterned on the substrate can include overlapping pairs of marks for alignment with other formed layers. The matched overlay pairs are formed in a complex pattern of subsequently formed layers. These matched overlay pairs are placed within the complex pattern of subsequent layers such that when aligned with the corresponding complex overlay pairs of the lower layer, the two layers are aligned. However, this alignment technique is not perfect and it is desirable to have an alignment technique that provides improved alignment.

Embodiments of the present disclosure provide a stacked pair mark structure including: a first periodic structure on a wafer, a first periodic structure including a first layer of material on a wafer; and a second periodic structure located adjacent to the first period In the region of the wafer of the structured structure, the second periodic structure includes a second layer of material disposed on the wafer; an acoustic wave emitting device on the wafer; and an acoustic wave receiving device on the wafer.

The present disclosure provides a semiconductor device including: an acoustic wave emitting device on a wafer; an acoustic wave receiving device on the wafer; a first periodic structure on the wafer, the first periodic structure including the first material; and a second A periodic structure is located on the wafer and the second periodic structure includes a second material.

Embodiments of the present disclosure provide a method of detecting an overlay error using sound waves, including: forming a first material layer on a semiconductor wafer, the first material layer including a first periodicity in a stacked pair of semiconductor wafer regions a second material layer is formed on the semiconductor wafer, the second material layer includes a second periodic structure in the overlap mark region; and the sound wave is transmitted across the first period using an acoustic wave emitting device disposed in the overlap mark region Both the sexual structure and the second periodic structure; detecting the sound wave using the acoustic wave receiving device; and determining the stacking error between the first material layer and the second material layer based on the sound wave detected by the sound wave receiving device.

The disclosure provides many different embodiments or examples to implement various features of the present invention. The following disclosure sets forth specific examples of various components and their arrangement to simplify the description. Of course, these specific examples are not intended to be limiting. For example, if the present disclosure describes that a first feature is formed on or over a second feature, that is, it may include an embodiment in which the first feature is in direct contact with the second feature. It is also possible to include embodiments in which additional features are formed between the first feature and the second feature described above, such that the first feature and the second feature may not be in direct contact. In addition, different examples of the following disclosure may reuse the same reference symbols and/or labels. These repetitions are not intended to limit the specific relationship between the various embodiments and/or structures discussed.

In addition, it is related to space. For example, "lower", "lower", "lower", "above", "higher" and similar terms are used to facilitate the description of one element or feature in the illustration and another. The relationship between components or features. These spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. In addition to this, the device may be turned to a different orientation (rotated 90 degrees or other orientation), and the spatially related words used herein may be interpreted the same.

As noted above, alignment techniques typically involve the use of alignment marks, which are sometimes referred to as overlay pairs. For example, the various layers to be patterned on the substrate can include overlapping pairs of marks for alignment with other formed layers. The matched stacked pair marks are formed in a complex pattern of a plurality of layers formed later. These matched overlay pairs are placed within the complex pattern of subsequent layers such that when aligned with the corresponding complex overlay pairs of the lower layer, the two layers are aligned. However, this alignment technique is not perfect and it is desirable to have an alignment technique that provides improved alignment.

In accordance with the principles described herein, overlay pairs from two different layers are designed to transmit or reflect sound waves. The stack of marks can be disposed in a semiconductor region in which a semiconductor region is provided with a transducer. The converter converts electrical energy into mechanical energy in the form of sound waves. The sound waves then pass through a first overlay mark associated with the first layer and a second overlay mark associated with the different layers. Sound waves (reflected from the overlay marks or through the overlay marks) can then be detected by the acoustic wave receiving device. The nature of the detected sound waves will vary based on the alignment between the first overlap mark and the second overlap mark. Therefore, by analyzing the detected sound waves, the alignment error can be determined.

Figure 1 shows a schematic of a stacked pair of symbol structures 100. The stacked pair of mark structures 100 are located within a particular region 102 within the semiconductor wafer. The stacked pair of mark structures 100 can be located within one or more layers of a semiconductor wafer. For example, the overlay mark structure 100 can be on a semiconductor substrate or any subsequently formed layer (eg, a metal layer or a dielectric layer). According to an embodiment of the present disclosure, the overlay pair structure 100 includes an acoustic wave emitting device 104, an acoustic wave receiving device 106, and a periodic structure region 112, and the periodic structure region 112 has a first periodic structure 108 and a second periodicity. Structure 110.

The semiconductor wafer in which the stacked pairs are provided may be a circular wafer for manufacturing an integrated circuit. In some embodiments, the overlay mark structure 100 can be located within a scribe line of a semiconductor wafer. A dicing line is a line that scribes a semiconductor wafer after a semiconductor process. However, in some embodiments, the overlay mark structure 100 can be located between the dicing lines and is therefore part of the final semiconductor wafer product.

The acoustic wave emitting device 104 can be an acoustic wave transmitter. In other words, the acoustic wave emitting device 104 is designed to emit sound waves along the surface of the substrate. In one embodiment, acoustic wave emitting device 104 is an interdigital transducer. The acoustic wave emitting device 104 can be designed to convert electrical signals into mechanical signals. In some embodiments, the overlay mark structure 100 can be located over a piezoelectric layer. Piezoelectric materials may experience mechanical strain or stress when current is applied. Therefore, the AC electrical signal applied to the acoustic wave transmitting device 104 can cause the surface acoustic wave signal to be emitted across the periodic structural region 112.

The periodic structure region 112 includes a first periodic structure 108 and a second periodic structure 110. In one embodiment, the first periodic structure 108 is formed along a first patterned layer formed on a semiconductor wafer. For example, the first patterned layer can be a polysilicon gate layer. Thus, the first periodic structure 108 can include a plurality of polysilicon features. These polysilicon features can be formed by a lithography process. For example, a polysilicon layer can be deposited. Next, a photoresist material may be disposed on the polysilicon layer. The photoresist material can then be exposed to the light source through the reticle and developed. The exposed regions of the polysilicon layer can then be removed through an etch process to produce a patterned polysilicon layer. As described in further detail below, the first periodic structure 108 can include a two-dimensional array of complex features. These features can be sized and spaced apart to produce the frequency distribution required to emit sound waves that are reflected by or reflected from the first periodic structure 108.

The second periodic structure 110 is similar to the first periodic structure 108. In particular, the second periodic structure 110 can include two-dimensional solid features whose features are similar in size and shape to those of the first periodic structure. The second periodic structure 110 can be associated with a second layer of material formed on the semiconductor wafer. The second periodic structure 110 is located throughout the pattern such that when the pattern of the second material layer is aligned with the pattern of the first material layer, the second periodic structure 110 is located adjacent the first periodic structure 108. The second periodic structure 110 is located adjacent the first periodic structure 108 such that when properly aligned, features from both the first periodic structure 108 and the second periodic structure 110 form a single unit having similar spacing throughout Two-dimensional array.

In the disclosed embodiment, the acoustic wave receiving device 106 is positioned on the opposite side of the periodic structural region 112 relative to the acoustic wave transmitting device 104. Accordingly, the acoustic wave receiving device 106 can be designed to detect sound waves as they are emitted through the first periodic structure 108 and the second periodic structure 110. The acoustic wave receiving device 106 is designed to convert mechanical energy into electrical energy. In other words, the acoustic wave receiving device 106 detects surface acoustic waves that are transmitted through the first periodic structure 108 and the second periodic structure 110, and converts those surface acoustic waves into electrical signals representing surface acoustic waves. The electrical signal can be analyzed to characterize the wave indicating that the first periodic structure 108 is aligned with the second periodic structure 110.

In some embodiments, acoustic wave receiving device 106 and acoustic wave transmitting device 104 may be located on the same side of periodic structural region 112. In such an embodiment, the acoustic wave receiving device 106 can be configured to detect surface acoustic waves as the surface acoustic waves are reflected by the first periodic structure 108 and the second periodic structure 110.

2A, 2B, and 2C show top views of the periodic structure for the overlay marks. In accordance with an embodiment of the present disclosure, FIG. 2 shows the first overlay mark 202 and the second overlay mark 204 that are correctly aligned. The first stack of marks 202 is a periodic structure, such as the first periodic structure 108 described above. The second stack of marks 204 is also a periodic structure, such as the second periodic structure 110 described above.

FIG. 2B shows an embodiment in which the first stack of marks 202 and the second stack of marks 204 are misaligned. In particular, the second overlay mark 204 is spaced further from the first overlay mark 202 than it should. Figure 2C shows an embodiment in which the first stack of marks 202 and the second stack of marks 204 are misaligned. In particular, the second overlay mark 204 is spaced closer to the first overlay mark 202 than it should be.

3A, 3B, and 3C are graphs showing acoustic signals corresponding to the arrangement of the periodic structures of FIGS. 2A, 2B, and 2C. Specifically, FIG. 3A shows sound wave signals corresponding to the positions of the first stack of marks 202 and the second stack of marks 204 shown in FIG. 2A. Figure 3B shows the acoustic signals corresponding to the positions of the first overlay mark 202 and the second overlay mark 204 shown in Figure 2B. Figure 3C shows the acoustic signals corresponding to the positions of the first stack of marks 202 and the second stack of marks 204 shown in Figure 2C.

Figure 3A shows a graph with a vertical axis 302 representing the amplitude and a horizontal axis 304 representing the frequency. The signal 308 is a sound wave signal generated when the overlapping marks are spaced apart as shown in FIG. 2A. The center frequency 306 of such a signal is indicated by a dashed line. Figure 3B shows the signal 310 associated with the first overlay mark 202 and the second overlay mark 204 shown in Figure 2B. In other words, because the overlay pairs are farther apart than they should, the center frequency of signal 310 is offset (less than) its center frequency 306. Similarly, Figure 3C shows the signal 312 associated with the first overlay mark 202 and the second overlay mark 204 shown in Figure 2C. In other words, because the overlay pairs are closer than they should, the center frequency of signal 312 is offset (greater than) its center frequency 306.

According to an example of the principles described herein, FIGS. 4A, 4B, and 4C are graphs showing reflected acoustic wave signals corresponding to the arrangement of the periodic structures of FIGS. 2A, 2B, and 2C. Specifically, FIG. 4A shows the reflected acoustic wave signals corresponding to the positions of the first overlapping mark 202 and the second overlapping mark 204 shown in FIG. 2A. Fig. 4B shows the reflected acoustic wave signal corresponding to the positions of the first overlapping mark 202 and the second overlapping mark 204 shown in Fig. 2B. Fig. 4C shows the reflected acoustic wave signal corresponding to the positions of the first overlapping mark 202 and the second overlapping mark 204 shown in Fig. 2C.

Figure 4A shows a graph with a vertical axis 302 representing the amplitude and a horizontal axis 304 representing the frequency. When the first overlay symbol 202 and the second overlay symbol 204 are spaced apart as shown in FIG. 2A, the signal 402 corresponds to the acoustic signal reflected from the first overlay symbol 202 and the second overlay symbol 204. The center frequency 306 of such a signal is indicated by a dashed line. Figure 4B shows the signal 404 reflected from the first overlay mark 202 and the second overlay mark 204 shown in Figure 2B. In other words, because the first overlay pair 202 and the second overlay token 204 are further apart than they should, the signal 404 is offset (less than) the center frequency 306 of the aligned signal 402. Similarly, Figure 4C shows the signal 406 reflected from the first overlay symbol 202 and the second overlay symbol 204 shown in Figure 2C. In other words, because the first overlay pair 202 and the second overlay token 204 are closer together than they should, the signal 406 is offset (greater than) the aligned signal 402.

FIGS. 5A, 5B, and 5C are graphs showing the transmitted acoustic wave signals corresponding to the configurations of the periodic structures of FIGS. 2A, 2B, and 2C. Specifically, FIG. 5A shows the transmitted acoustic wave signals corresponding to the positions of the first overlapping mark 202 and the second overlapping mark 204 shown in FIG. 2A. Figure 5B shows the transmitted acoustic wave signal corresponding to the positions of the first overlay mark 202 and the second overlay mark 204 shown in Figure 2B. Figure 5C shows the transmitted acoustic wave signal corresponding to the positions of the first overlay mark 202 and the second overlay mark 204 shown in Figure 2C.

Figure 5A shows a graph with a vertical axis 302 representing the amplitude and a horizontal axis 304 representing the frequency. When the first overlay symbol 202 and the second overlay symbol 204 are spaced apart as shown in FIG. 2A, the signal 502 corresponds to the acoustic signal transmitted through the first overlay symbol 202 and the second overlay symbol 204. The center frequency 306 of such a signal is indicated by a dashed line. Figure 5B shows the signal 504 being transmitted through the first overlay mark 202 and the second overlay mark 204 shown in Figure 2B. In other words, because the first overlay pair 202 and the second overlay token 204 are further apart than they should, the signal 504 is offset (less than) the center frequency 306 of the aligned signal 502. Similarly, Figure 5C shows a signal 506 that is transmitted through the first overlay mark 202 and the second overlay mark 204 shown in Figure 2C. In other words, because the first overlay pair 202 and the second overlay token 204 are closer together than they should, the signal 506 is offset (greater than) the aligned signal 502.

Figures 6A and 6B show schematic views of the shapes of the features used to overlap the marks. In accordance with an embodiment of the present disclosure, FIG. 6A shows a first overlay mark 602 having a periodic structure adjacent to a second overlay mark 604 having a periodic structure. The features of both the first stack of indicia 602 and the second stack of indicia 604 are generally rectangular in shape. More specifically, as shown, the first overlay mark 602 and the second overlay mark 604 have a square shape. Figure 6B shows a first overlay mark 612 having a periodic structure adjacent to a second overlay mark 614 having a periodic structure. The features of both the first stack of indicia 612 and the second stack of indicia 614 are generally elliptical in shape. Other shapes are also considered. For example, the features of the stacked pairs described herein can have a circular shape.

Figures 7A through 7G show schematic diagrams of various configurations of stacked pairs of marks. In accordance with an embodiment of the present disclosure, FIG. 7A shows a first overlay mark having a set of features 702 that circumscribe or surround features 704 of the second overlay mark. While only one revolution feature 702 is shown surrounding feature 704, it should be understood that some examples may include many rows of feature components 702 surrounding feature 704. When feature 702 is not aligned with feature 704, the characteristics of the acoustic waves that are transmitted through or reflected from features 702 and 704 will indicate the nature of the misalignment.

Figure 7B shows a schematic diagram of the interleaved pair of first and second pairs of marks. For example, features 702 from the first stack of tokens are arranged in rows. Similarly, features 704 from the second overlay pair are arranged in rows. The rows of different types of features 702 and 704 are alternated. When feature 702 is not aligned with feature 704, the characteristics of the acoustic waves that are transmitted through or reflected from features 702 and 704 will indicate the nature of the misalignment.

Figure 7C shows a schematic diagram of the interleaved pair of first and second pairs of marks. For example, features 702 from the first overlay pair are gathered at the upper left and lower right. Features 704 from the second stack of marks are gathered in the upper right and lower left. This configuration may also allow for alignment to be determined in more than one direction. For example, the alignment can be determined in a first direction and a second direction orthogonal to the first direction. When feature 702 is not aligned with feature 704, the characteristics of the acoustic waves that are transmitted through or reflected from features 702 and 704 will indicate the nature of the misalignment.

Figure 7D shows a schematic view of the first stack of marks adjacent to the second stack of marks in a diagonal manner. For example, feature 702 from the first overlay pair of symbols is located at the lower left. Features 704 from the second stack of marks are located on the upper right. This configuration may also allow for alignment to be determined in more than one direction. For example, the alignment can be determined in a first direction and a second direction orthogonal to the first direction. When feature 702 is not aligned with feature 704, the characteristics of the acoustic waves that are transmitted through or reflected from features 702 and 704 will indicate the nature of the misalignment.

Figure 7E shows a schematic diagram in which the first stack of marks and the second pair of marks are staggered. For example, features 702 from the first stack of tokens are arranged in rows. Similarly, features 704 from the second overlay pair are arranged in rows. The rows of different types of features 702 and 704 are alternating. However, feature 704 has more rows than the rows that feature 702 has. When feature 702 is not aligned with feature 704, the characteristics of the acoustic waves that are transmitted through or reflected from features 702 and 704 will indicate the nature of the misalignment.

Fig. 7F shows a schematic diagram in which the first stack of marks and the second pair of marks are staggered. For example, features 702 from the first stack of indicia are positioned in rows. Similarly, features 704 from the second overlay pair are positioned in rows. The rows of different types of features 702 and 704 are alternated. However, feature 704 has more rows than the rows that feature 702 has. Figure 7F is similar to Figure 7E except that it extends in different directions. When feature 702 is not aligned with feature 704, the characteristics of the acoustic waves that are transmitted through or reflected from features 702 and 704 will indicate the nature of the misalignment.

Figure 7G shows a schematic diagram in which the first stack of marks and the second pair of marks are staggered. For example, feature 702 from the first overlay mark and feature 704 from the second overlay mark are disposed in the checkerboard pattern. This configuration may also allow for alignment to be determined in more than one direction. For example, the alignment can be determined in a first direction and a second direction orthogonal to the first direction. When feature 702 is not aligned with feature 704, the characteristics of the acoustic waves that are transmitted through or reflected from features 702 and 704 will indicate the nature of the misalignment.

Figure 8 shows a schematic diagram of various periodic structures, acoustic wave emitting devices, and acoustic wave receiving devices. In accordance with embodiments of the present disclosure, four different overlay pairs of symbols 802, 804, 806, 808 are disposed in a square pattern within the periodic structure region 110. In some embodiments, each of the stacked pairs of marks can be associated with a different layer of material. In some embodiments, two stacked pairs of marks may be associated with the same material, and the other two stacked pairs of marks may be associated with different materials. The overlay marks 802, 804, 806, 808 may each include a periodic structure having a plurality of features in the periodic pattern, such as the patterns shown in Figures 6A through 7G above.

In one embodiment, device 812 is an acoustic wave emitting device configured to emit acoustic waves across stacking marks 802 and 804. This sound wave can be received by device 814. Similarly, device 816 can be an acoustic wave emitting device configured to emit acoustic waves across stacking marks 806 and 808. This sound wave can be received by device 818. Moreover, device 820 can be an acoustic wave emitting device configured to emit acoustic waves across stacking marks 802 and 806. This sound wave can be received by device 824. Similarly, device 822 can be an acoustic wave emitting device configured to emit acoustic waves across stacking marks 804 and 808. This sound wave can be received by device 826. Therefore, the configuration shown in Fig. 8 can be used for detection.

Figure 9 shows a schematic diagram of a plurality of stacked pairs of markers in series. In accordance with an embodiment of the present disclosure, the plurality of stacked pairs of symbol regions 900a, 900b, 900c are arranged in series. In other words, they are arranged along a line in the direction of the sound waves that are emitted through the overlap mark areas 900a, 900b, 900c. Each of the stacked pair of mark areas 900a, 900b, 900c includes an acoustic wave emitting device, an acoustic wave receiving device, and at least two overlapping pairs of symbols including a periodic structure.

Figure 10 shows a schematic diagram of a plurality of stacked pairs of marks in parallel. In accordance with an embodiment of the present disclosure, the plurality of stacked pairs of mark regions 1000a, 1000b, 1000c are arranged in parallel. In other words, they are arranged along a line orthogonal in the direction of the sound waves emitted through the overlap mark areas 1000a, 1000b, 1000c. Each of the stacked pair of mark areas 1000a, 1000b, 1000c includes an acoustic wave emitting device, an acoustic wave receiving device, and at least two overlapping pairs of symbols including a periodic structure.

Figures 11A through 11D show schematic views of the formation of stacked pairs of marks. In accordance with an embodiment of the present disclosure, FIG. 11A shows two different portions of process wafer 1102. The first part is the production part 1101, and the second part is the test part 1103. The production section 1101 is a part of a wafer on which an integrated circuit is fabricated. The test portion 1103 is a portion of the wafer, and the overlay marks can be formed in the test portion 1103 to test the alignment of the patterns of the different layers formed in the production portion 1101. For purposes of discussion, the test portion 1103 can correspond to the periodic structure region 112 in the content described with Figure 1.

In accordance with an embodiment of the present disclosure, test portion 1103 includes a piece electrical 1104, a first hard mask layer 1108, and a second hard mask layer 1106. As described above, the overlay mark can be located above the piezoelectric layer. Piezoelectric materials may experience mechanical strain or stress when current is applied. Therefore, the AC electrical signal applied to the acoustic wave transmitting device can cause the surface acoustic wave signal to be emitted across the test portion 1103.

At the same time, the production portion 1101 can have a first material layer 1114 to be patterned. The first material layer 1114 can be one of a variety of materials. For example, the first material layer 1114 can be a polysilicon layer to form a gate structure, or a metal layer to form an internal interconnect. After depositing the first material layer 1114, a first patterned photoresist layer is deposited, exposed to the light source through a mask, and developed. After development, the photoresist feature 1110 remains in the production portion 1101, and the photoresist feature 1112 remains in the test portion 1103. The photoresist feature 1112 can correspond to a first overlay symbol comprising a plurality of periodic structures.

FIG. 11B shows an etch process 1120 to pattern the second hard mask layer 1106 in the test portion 1103 and the first material layer 1114 in the production portion 1101. The second hard mask layer 1106 can be selected to have a material that is removable in the same etch process for patterning the first material layer 1114 in the production portion 1101. After the etch process, the photoresist features 1110 and 1112 can be removed.

Figure 11C shows an additional layer. In particular, Figure 11C shows the interlayer dielectric layer 1132 deposited on the first material layer features in the production portion 1101. Production portion 1101 also includes a second material layer 1134 deposited on interlayer dielectric layer 1132. The second material layer 1134 can be one of a variety of materials. For example, the second material layer 1134 can be a metal material used to form metal lines or vias.

Next, a second photoresist layer is deposited. The second photoresist layer (after being exposed and developed) includes a first photoresist feature 1130 in the production portion 1101 and a second photoresist feature 1136 in the test portion 1103. The photoresist feature 1136 corresponds to a second stack of indicia comprising a plurality of periodic features. The first photoresist feature 1130 and the second photoresist feature 1136 are formed using the same mask. The reticle is designed such that when the first photoresist feature 1130 is aligned with the features of the first material layer 1114, the second photoresist features 1136 are disposed such that they form a single feature with the features of the second hard mask layer 1106 Overlap marks (for example: as shown in Figure 2A). In other words, the features of the second hard mask layer 1106 and all of the features of the second photoresist feature 1136 will have similar spacing. This produces a desired frequency signal in the detected sound waves through the feature. If the first photoresist feature 1130 is not properly aligned with the first material layer 1114 (eg, as shown in Figures 2B and 2C), the second photoresist feature 1136 is opposite the second hard mask layer The features of 1106 are not properly spaced apart.

Figure 11D shows an etch process 1140. After forming the first photoresist feature 1130 and the second photoresist feature 1136, an etch process can be performed to pattern the second material layer 1134 and the first hard mask layer 1108. The features of the second hard mask layer 1106 and the second photoresist feature 1136 define a pattern to be transferred to the first hard mask layer 1108. In some embodiments, the etch process 1140 can be selected along with the materials of the first hard mask layer 1108 and the second material layer 1134 such that the first hard mask layer 1108 and the second material layer 1134 are processed by the same etch process. Was removed.

FIG. 11D shows the state after the etching process 1140, and after the second photoresist feature 1136 and the second hard mask layer 1106 are removed. After these features are removed, the remaining features 1142 and 1144 of the first hard mask layer 1108 are retained. Feature component 1142 can correspond to a first overlay symbol (eg, first periodic structure 108 of FIG. 1), and feature component 1144 can correspond to a second overlay symbol (eg, second periodic structure 110 of FIG. 1) ). After the features 1142 and 1144 are formed, sound waves can be emitted across the features 1142 and 1144 to determine if the features 1134 and the features of the first material layer 1114 are properly aligned.

Figure 12 shows a flow chart of a method for detecting aliasing errors using sound waves. In accordance with an embodiment of the present disclosure, method 1200 includes an operation 1202 of forming a first material layer on a semiconductor wafer, the first material layer including a first periodic structure within a stacked pair of semiconductor wafer regions. In accordance with an embodiment of the present disclosure, method 1200 includes an operation 1204 of forming a second material layer on a semiconductor wafer, the second material layer including a second periodic structure in the stacked pair of mark regions. In accordance with an embodiment of the present disclosure, method 1200 includes an operation 1206 of transmitting acoustic waves across both the first periodic structure and the second periodic structure using acoustic wave emitting devices disposed within the stacked pair of markers. In accordance with an embodiment of the present disclosure, method 1200 includes an operation 1208 of detecting sound waves using a sound wave receiving device. According to an embodiment of the present disclosure, the method 1200 includes an operation 1210 of determining a stacking error between the first material layer and the second material layer based on the sound waves detected by the acoustic wave receiving device.

In accordance with an embodiment of the present disclosure, the stacked mark structure includes a first periodic structure on the wafer, the first periodic structure including a first layer of material on the wafer. The stack of mark structures further includes a second periodic structure located in a region adjacent to the wafer of the first periodic structure, the second periodic structure including a second layer of material disposed on the wafer. The stack-to-mark structure further includes an acoustic wave emitting device on the wafer and an acoustic wave receiving device on the wafer.

In some embodiments, the acoustic wave receiving device is adjacent to the acoustic wave emitting device.

In some embodiments, the features of the first periodic structure and the features of the second periodic structure are located in alternating complex columns.

In some embodiments, the features of the first periodic structure and the features of the second periodic structure are arranged in a checkerboard pattern.

In some embodiments, the stacked pair of markers further includes a piezoelectric layer below the first periodic structure and the second periodic structure.

In accordance with an embodiment of the present disclosure, a semiconductor device includes an acoustic wave emitting device on a wafer, an acoustic wave receiving device on the wafer, and a first periodic structure on the wafer, the first periodic structure including the first material. The semiconductor device further includes a second periodic structure positioned on the wafer, the second periodic structure including the second material.

In some embodiments, the acoustic wave emitting device comprises an interdigital transducer.

In some embodiments, the acoustic wave emitting device comprises an acoustic wave emitter.

In accordance with an embodiment of the present disclosure, a method of detecting an overlay error using sound waves includes forming a first material layer on a semiconductor wafer, the first material layer including a first periodic structure within a stacked pair of semiconductor wafer regions. The method of using sound waves to detect overlay errors further includes forming a second material layer on the semiconductor wafer, the second material layer including a second periodic structure in the stacked pair of marks. The method of using sound waves to detect the overlay error further includes using an acoustic wave transmitting device disposed in the overlap-pair mark region to emit sound waves across both the first periodic structure and the second periodic structure. The method of using sound waves to detect the overlay error further includes using a sound wave receiving device to detect sound waves. The method of using sound waves to detect the overlay error further includes determining a stacking error between the first material layer and the second material layer based on the sound waves detected by the sound wave receiving device.

In some embodiments, the method of using sound waves to detect the overlay error further comprises determining the focus curve by analyzing the detected sound waves.

The foregoing summary of the invention is inferred by the claims It will be understood by those of ordinary skill in the art, and other processes and structures may be readily designed or modified on the basis of the present disclosure, and thus achieve the same objectives and/or achieve the same embodiments as those described herein. The advantages. Those of ordinary skill in the art should also understand that such equivalent structures are not departing from the spirit and scope of the invention. Various changes, permutations, or alterations may be made in the present disclosure without departing from the spirit and scope of the invention.

100‧‧‧Stacked mark structure

102‧‧‧Specific areas

104‧‧‧Sonic launcher

106‧‧‧Sonic receiver

108‧‧‧First periodic structure

110‧‧‧Second periodic structure

112‧‧‧Periodic structural area

202‧‧‧First stack of marks

204‧‧‧Second stack of marks

302‧‧‧ vertical axis

304‧‧‧ horizontal axis

306‧‧‧ center frequency

308, 310, 312‧‧‧ signals

402, 404, 406‧‧‧ signals

502, 504, 506‧‧‧ signals

602‧‧‧ first stack of marks

604‧‧‧Second stack of marks

612‧‧‧First stack of marks

614‧‧‧Second stack of marks

702, 704‧‧‧Feature parts

802, 804, 806, 808‧‧ ‧ pairs of marks

812, 814, 816, 818, 820, 822, 824, 826‧‧‧ devices

900a, 900b, 900c‧‧‧ stacking mark area

1000a, 1000b, 1000c‧‧‧ stacking mark area

1101‧‧‧Production section

1102‧‧‧Process wafer

1103‧‧‧Test section

1104‧‧‧Electrical components

1106‧‧‧Second hard mask layer

1108‧‧‧First hard mask layer

1110‧‧‧Light-resistance features

1112‧‧‧Photoresist features

1114‧‧‧First material layer

1120‧‧‧ etching process

1130‧‧‧First photoresist feature

1132‧‧‧Interlayer dielectric layer

1134‧‧‧Second material layer

1136‧‧‧Second photoresist features

1140‧‧‧ etching process

1142‧‧‧Feature parts

1144‧‧‧Feature parts

1200‧‧‧ method

1202-1210‧‧‧ operation

The opinions of the present disclosure can be better understood from the following embodiments and the accompanying drawings. The schematic diagrams are exemplary and different features are not illustrated herein. The dimensions of the different features may be arbitrarily increased or decreased for clarity of discussion. Figure 1 is a schematic illustration of a stacked pair of markers in accordance with an embodiment of the present disclosure. 2A, 2B, and 2C are top views of periodic structures for stacked pairs in accordance with an embodiment of the present disclosure. 3A, 3B, and 3C are graphs of acoustic signals corresponding to the arrangement of the periodic structures of Figs. 2A, 2B, and 2C according to the disclosed embodiment. 4A, 4B, and 4C are graphs showing reflected acoustic wave signals corresponding to the arrangement of the periodic structures of FIGS. 2A, 2B, and 2C in accordance with an embodiment of the present disclosure. 5A, 5B, and 5C are graphs of emitted acoustic wave signals corresponding to the configurations of the periodic structures of FIGS. 2A, 2B, and 2C according to the disclosed embodiment. 6A and 6B are schematic views of the shape of a feature for overlapping marks according to an embodiment of the present disclosure. 7A through 7G are schematic views of various configurations of stacked pairs of marks in accordance with an embodiment of the present disclosure. Figure 8 is a schematic diagram of various periodic structures, acoustic wave emitting devices, and acoustic wave receiving devices in accordance with embodiments of the present disclosure. Figure 9 is a schematic illustration of a plurality of stacked pairs of mark regions in series in accordance with an embodiment of the present disclosure. Figure 10 is a schematic illustration of a plurality of stacked pairs of mark regions in parallel in accordance with an embodiment of the present disclosure. 11A through 11D are schematic views showing the formation of stacked pairs of marks according to an embodiment of the present disclosure. Figure 12 is a flow chart of a method for detecting overlay errors using sound waves in accordance with an embodiment of the present disclosure.

Claims (20)

A stacked pair mark structure comprising: a first periodic structure on a wafer, the first periodic structure comprising a first layer of material on the wafer; a second periodic structure located adjacent to the first In a region of the periodic structure of the wafer, the second periodic structure includes a second layer of material disposed on the wafer; an acoustic wave emitting device on the wafer; and an acoustic wave receiving device on the wafer . The stacked mark structure according to claim 1, wherein the first periodic structure and the second periodic structure are located between the acoustic wave transmitting device and the acoustic wave receiving device. The stacking mark structure of claim 1, wherein the sound wave receiving device is adjacent to the sound wave emitting device. The stacked-to-mark structure of claim 1, wherein the first periodic structure comprises a two-dimensional array of complex features. The overlay structure according to claim 4, wherein the feature in the two-dimensional array has one of the following: a rectangle, an ellipse or a square. The stacked mark structure of claim 1, wherein the features of the first periodic structure and the features of the second periodic structure are staggered. The stacked mark structure of claim 6, wherein the feature of the first periodic structure and the feature of the second periodic structure are located in alternating plural columns. The stacked mark structure according to claim 6, wherein the feature of the first periodic structure and the feature of the second periodic structure are arranged in a checkerboard pattern. The stacked mark structure of claim 1, wherein the feature of the first periodic structure surrounds the feature of the second periodic structure. The stacked mark structure of claim 1, further comprising a piezoelectric layer below the first periodic structure and the second periodic structure. The stacked mark structure of claim 1, further comprising a plurality of regions of the wafer, each of the regions comprising a plurality of additional periodic structures, an additional acoustic wave receiving device, and an additional acoustic wave emitting device. The above regions are arranged in series. The stacked mark structure of claim 1, further comprising a plurality of regions of the wafer, each of the regions comprising a plurality of additional periodic structures, an additional acoustic wave receiving device, and an additional acoustic wave emitting device, The areas are arranged in parallel. A semiconductor device comprising: an acoustic wave emitting device on a wafer; an acoustic wave receiving device on the wafer; a first periodic structure on the wafer, the first periodic structure comprising a first material; And a second periodic structure on the wafer, the second periodic structure comprising a second material. The semiconductor device of claim 13, wherein the acoustic wave emitting device comprises an interdigital transducer. The semiconductor device of claim 13, wherein the acoustic wave emitting device comprises an acoustic wave transmitter. A method for detecting an overlay error using sound waves, comprising: forming a first material layer on a semiconductor wafer, the first material layer including a first period in a stack of mark regions of the semiconductor wafer a second material layer is formed on the semiconductor wafer, the second material layer includes a second periodic structure in the overlap mark region; and an acoustic wave emission disposed in the overlap mark region is used And transmitting, by the apparatus, a sound wave spanning both the first periodic structure and the second periodic structure; detecting the sound wave by using an acoustic wave receiving device; and determining the first sound based on the sound wave detected by the sound wave receiving device A stack of errors between a layer of material and the second layer of material described above. A method for detecting a stacking error using sound waves as described in claim 16 wherein said sound wave detected by said sound wave receiving means is transmitted through said first periodic structure and said second periodic structure Acoustic waves, or sound waves reflected by the first periodic structure and the second periodic structure described above. The method for detecting an overlay error using sound waves as described in claim 16 wherein the step of determining the overlap error comprises using one of a scattering frequency number, a scattering angle, a half height width, and a center frequency. The above sound waves detected are analyzed. A method for detecting a stacking error using sound waves as described in claim 16, wherein the step of determining the stacking error comprises determining a first direction and a second direction orthogonal to the first direction Error. The method for detecting a pairwise error using sound waves as described in claim 16 of the patent application, further comprising determining a focus curve by analyzing the detected sound waves.